Achieving strong adhesion between wet materials (i.e., tissues and hydrogels) is challenging. Existing adhesives are weak, toxic, incompatible with wet and soft surfaces, or restricted to specific functional groups from the wet materials. The approach reported here uses biocompatible polymer chains to achieve strong adhesion and retain softness, but requires no functional groups from the wet materials. In response to a trigger, the polymer chains form a network, in topological entanglement with the two polymer networks of the wet materials, stitching them together like a suture at the molecular scale. To illustrate topological adhesion, pH is used as a trigger. The stitching polymers are soluble in water in one pH range but form a polymer network in another pH range. Several stitching polymers are selected to create strong adhesion between hydrogels in full range of pH, as well as between hydrogels and various porcine tissues (liver, heart, artery, skin, and stomach). The adhesion energy above 1000 J m⁻² is achieved when the stitching polymer network elicits the hysteresis in the wet materials. The molecular suture can be designed to be permanent, transient, or removable on‐demand. The topological adhesion may open many opportunities in complex and diverse environments.

中文翻译：

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湿材料的拓扑粘合

要在湿的材料（例如，薄纸和水凝胶）之间实现牢固的附着力是一项挑战。现有的粘合剂是弱的，有毒的，与湿的和软的表面不相容，或限于湿材料中的特定官能团。此处报道的方法使用生物相容性聚合物链来实现强粘附力并保持柔软性，但不需要湿材料中的官能团。响应触发，聚合物链与湿材料的两个聚合物网络以拓扑缠结的方式形成网络，将它们像缝合线一样在分子规模上缝合在一起。为了说明拓扑结构的附着力，使用pH值作为触发条件。缝合聚合物在一个pH范围内可溶于水，但在另一pH范围内形成聚合物网络。选择了几种缝合聚合物，以在整个pH值范围内的水凝胶之间以及水凝胶与各种猪组织（肝脏，心脏，动脉，皮肤和胃）之间形成强粘附力。1000 J m以上的附着力当缝合聚合物网络引起湿材料中的磁滞时，可达到^-2。可以将分子缝合线设计为永久性，瞬时性或按需移动。拓扑粘附可能会在复杂多样的环境中打开许多机会。